rpc: add "ischange: true" in wallet gettransaction decoded tx output

src/core_io.h

@@ -21,6 +21,7 @@ class SigningProvider;
 class uint256;
 class UniValue;
 class CTxUndo;
+class CTxOut;
 
 /**
  * Verbose level for block's transaction
@@ -46,6 +47,6 @@ std::string FormatScript(const CScript& script);
 std::string EncodeHexTx(const CTransaction& tx);
 std::string SighashToStr(unsigned char sighash_type);
 void ScriptToUniv(const CScript& script, UniValue& out, bool include_hex = true, bool include_address = false, const SigningProvider* provider = nullptr);
-void TxToUniv(const CTransaction& tx, const uint256& block_hash, UniValue& entry, bool include_hex = true, const CTxUndo* txundo = nullptr, TxVerbosity verbosity = TxVerbosity::SHOW_DETAILS);
+void TxToUniv(const CTransaction& tx, const uint256& block_hash, UniValue& entry, bool include_hex = true, const CTxUndo* txundo = nullptr, TxVerbosity verbosity = TxVerbosity::SHOW_DETAILS, std::function<bool(const CTxOut&)> is_change_func = {});
 
 #endif // BITCOIN_CORE_IO_H

src/core_write.cpp

@@ -168,7 +168,7 @@ void ScriptToUniv(const CScript& script, UniValue& out, bool include_hex, bool i
     out.pushKV("type", GetTxnOutputType(type));
 }
 
-void TxToUniv(const CTransaction& tx, const uint256& block_hash, UniValue& entry, bool include_hex, const CTxUndo* txundo, TxVerbosity verbosity)
+void TxToUniv(const CTransaction& tx, const uint256& block_hash, UniValue& entry, bool include_hex, const CTxUndo* txundo, TxVerbosity verbosity, std::function<bool(const CTxOut&)> is_change_func)
 {
     CHECK_NONFATAL(verbosity >= TxVerbosity::SHOW_DETAILS);
 
@@ -243,6 +243,11 @@ void TxToUniv(const CTransaction& tx, const uint256& block_hash, UniValue& entry
         UniValue o(UniValue::VOBJ);
         ScriptToUniv(txout.scriptPubKey, /*out=*/o, /*include_hex=*/true, /*include_address=*/true);
         out.pushKV("scriptPubKey", std::move(o));
+
+        if (is_change_func && is_change_func(txout)) {
+            out.pushKV("ischange", true);
+        }
+
         vout.push_back(std::move(out));
 
         if (have_undo) {

src/rpc/rawtransaction.cpp

@@ -118,6 +118,7 @@ static std::vector<RPCResult> DecodeTxDoc(const std::string& txid_field_doc)
                 {RPCResult::Type::STR_AMOUNT, "value", "The value in " + CURRENCY_UNIT},
                 {RPCResult::Type::NUM, "n", "index"},
                 {RPCResult::Type::OBJ, "scriptPubKey", "", ScriptPubKeyDoc()},
+                {RPCResult::Type::BOOL, "ischange", /*optional=*/true, "Output script is change (only if wallet transaction and true for selected rpcwallet)"},
             }},
         }},
     };

src/wallet/rpc/transactions.cpp

@@ -796,7 +796,16 @@ RPCHelpMan gettransaction()
 
     if (verbose) {
         UniValue decoded(UniValue::VOBJ);
-        TxToUniv(*wtx.tx, /*block_hash=*/uint256(), /*entry=*/decoded, /*include_hex=*/false);
+        TxToUniv(*wtx.tx,
+                /*block_hash=*/uint256(),
+                /*entry=*/decoded,
+                /*include_hex=*/false,
+                /*txundo=*/nullptr,
+                /*verbosity=*/TxVerbosity::SHOW_DETAILS,
+                /*is_change_func=*/[&pwallet](const CTxOut& txout) EXCLUSIVE_LOCKS_REQUIRED(pwallet->cs_wallet) {
+                                        AssertLockHeld(pwallet->cs_wallet);
+                                        return OutputIsChange(*pwallet, txout);
+                                    });
         entry.pushKV("decoded", std::move(decoded));
     }
 

test/functional/wallet_basic.py

@@ -542,13 +542,16 @@ class WalletTest(BitcoinTestFramework):
         destination = self.nodes[1].getnewaddress()
         txid = self.nodes[0].sendtoaddress(destination, 0.123)
         tx = self.nodes[0].gettransaction(txid=txid, verbose=True)['decoded']
-        output_addresses = [vout['scriptPubKey']['address'] for vout in tx["vout"]]
+        assert len(tx["vout"]) > 1
-        assert len(output_addresses) > 1
+        for vout in tx["vout"]:
-        for address in output_addresses:
+            address = vout['scriptPubKey']['address']
             ischange = self.nodes[0].getaddressinfo(address)['ischange']
             assert_equal(ischange, address != destination)
             if ischange:
                 change = address
+                assert vout["ischange"]
+            else:
+                assert "ischange" not in vout
         self.nodes[0].setlabel(change, 'foobar')
         assert_equal(self.nodes[0].getaddressinfo(change)['ischange'], False)